Clock Synchronization Over Fiber

1. A method of conducting a seismic survey, comprising: synchronizing a plurality of seismic devices over a fiber optic network using a recovered master clock signal, wherein at least one of the seismic devices is separated from a master clock by at least one other of the seismic devices, wherein the master clock and the plurality of seismic devices are arranged in at least one of: (i) a linear topology and (ii) a tree topology; encoding the master clock signal in a data stream along with at least one of i) a signal containing seismic data, and 2) a signal containing command and control information, the data stream comprising at least one of a 4B5B bit stream and a 8B10B bit stream; transmitting the data stream directly to one of the at least one other of the seismic devices; and propagating the master clock signal to the at least one of the seismic devices through subsequent seismic devices of the at least one other of the seismic devices by performing at each subsequent seismic device: recovering the master clock signal from a received data stream at the subsequent device; locking a local clock at the subsequent device to the master clock with the recovered master clock signal using a locking circuit; encoding the local clock signal as the master clock signal in a data stream, the data stream comprising at least one of a 4B5B bit stream and a 8B10B bit stream; and transmitting the data stream directly to at least one subsequent seismic devices.

2. The method of claim 1 , using a phase-locked loop circuit to lock the local clock with the master clock.

3. The method of claim 1 , wherein the master clock signal received by each of the plurality of seismic devices is one of: (i) directly received from the master clock and (ii) indirectly received through propagation using a local clock in the at least one other of the plurality of seismic devices.

4. A system for conducting a seismic survey, comprising: a master clock configured to generate a master clock signal; a plurality of seismic devices in communication with the master clock, wherein at least one of the seismic devices receives the master clock signal through the at least one other of the seismic devices, at least one of the seismic devices comprises seismic sensors, and a network of fiber optics configured to connect the master clock and the plurality of seismic devices; wherein the network of fiber optics is configured to transmit seismic data signals on the same physical channel as the master clock signal; wherein the master clock and the plurality of seismic devices are arranged in at least one of: (i) a linear topology and (ii) a tree topology, and at least one of the seismic devices comprises seismic sensors; and wherein the at least one other of the seismic devices comprises a local clock and is configured for: propagating the master clock signal to the at least one of the seismic devices through subsequent seismic devices of the at least one other of the seismic devices by performing at each subsequent seismic device: recovering the master clock signal from a received data stream at the subsequent device; locking the local clock to the master clock using the recovered master clock signal; and encoding the local clock signal as the master clock signal in a data stream and transmitting the data stream to at least one subsequent seismic device; and transmitting the data stream directly to at least one subsequent seismic devices.

5. The system of claim 4 , wherein each of the plurality of seismic devices comprises: a phase-locked loop circuit configured to lock the local clock with the master clock signal.

6. The system of claim 4 , wherein each of the plurality of seismic devices is configured to receive the master clock signal from one of: (i) a direct link to the master clock and (ii) an indirect link through the at least one other of the plurality of seismic devices.